Computer realizing high-speed access and data protection of storage device, computer system, and i/o request processing method

ABSTRACT

In a computer, a logical partition for calculation in which an OS and an application operate and a logical partition for storage for providing a storage function are constructed. In the logical partition for calculation, a device corresponding to a storage device is provided, while the logical partition for storage provides a volume. A memory space that can be shared by the both logical partitions is prepared, and management information describing a sorting destination or a sorting method of an I/O request issued by an application is provided in the memory. If the logical partition for calculation receives an I/O request from the application, the partition refers to the management information and sorts the I/O request to the storage device or the logical partition for storage. The logical partition for storage processes the received I/O request by the storage function and transmits the result to the storage device.

This is a continuation application of U.S. Ser. No. 14/583,883, filedDec. 29, 2014, which is a continuation application of U.S. Ser. No.13/807,410, filed Dec. 28, 2012, now U.S. Pat. No. 8,935,448. Thisapplication claims priority from National Stage of PCT/JP2012/007983,filed Dec. 13, 2012. The entire disclosures of all of the applicationslisted above are hereby incorporated by reference.

TECHNICAL FIELD

The present invention relates to a computer which realizes dataprotection while bringing out access performances of a storage device, acomputer system, and an I/O request processing method.

BACKGROUND ART

In processing of transactions for important data, a storage systemprovided with high data protection functions is indispensable. On theother hand, in primary processing or search/analysis processing capableof retry processing, high speed is given emphasis in some cases.

At present, high-speed devices to be mounted on servers and storagesincluding products such as PCIe-SSD, which couples an SSD (Solid StateDrive) with a high-speed protocol such as PCIe (PCI Express), andproducts such as All Flash Storage on which only an SSD is mounted, haveappeared.

CITATION LIST Patent Literature

[PTL 1] Japanese Patent Laid-Open No. 2008-97225

[PTL 2] U.S. Patent No. 2011/0289267

SUMMARY OF INVENTION Technical Problem

As described in PTL 1, a high-performance storage system utilizing therespective characteristics of both a low-speed device such as an HDD(Hard Disk Drive) and a high-speed device such as an SSD has beenproposed. However, in this case, a storage controller makes a bottleneckand there is a problem that the performances of the high-speed devicesuch as the SSD cannot be fully brought out. On the other hand, bydirectly coupling a high-speed device to a server, the performance canbe brought out without going through the storage controller, but thereis a problem that storage functions such as a data protection functionprovided in the storage controller cannot be fully utilized.

Moreover, as in PTL 2, in order to improve a Read performance of anapplication by utilizing a high-speed device, there is a method in whichthe high-speed device is directly coupled to the server, the high-speeddevice is used for a cache application, and the Write from theapplication is handled by writing data via write-through in the storagedevice coupled to an external device so as to realize both thehigh-speed access and data protection, but it is not necessary toprotect data of all the write data and there is a problem that the Writeperformance cannot be fully brought out.

The present invention has an object to provide data access means whichcan bring out both functionality of a storage controller and an I/Operformance of a storage device in data access to the storage device.

Solution to Problem

In the present invention, in order to solve at least one of theabove-described problems, a computer is logically partitioned, and alogical partition for compute and a logical partition for storage areprepared. Regarding I/O from the compute partition, it is determinedwhether the logical partition for storage is passed or not in accordancewith I/O contents, the I/O is sorted, and an access is made to a storagedevice group.

Moreover, in the present invention, in order to solve at least one ofthe above-described problems, a computer for compute and a computer forstorage are prepared, and regarding I/O from the computer for compute,it is determined whether the computer for storage is passed or not inaccordance with I/O contents, the I/O is sorted, and an access is madeto a storage device group.

Advantageous Effects of Invention

According to the present invention, a computer capable of flexible useaccording to user needs for a case where a high-speed access to astorage device is needed and for a case where data is to be protectedcan be provided.

BRIEF DESCRIPTION OF DRAWINGS

[FIG. 1]

FIG. 1 is a block diagram for explaining a configuration example of acomputer system in Embodiment 1.

[FIG. 2]

FIG. 2 is a diagram schematically illustrating a logical configurationexample of a node in Embodiment 1.

[FIG. 3]

FIG. 3 is a diagram illustrating a configuration example of a storagecontrol program in Embodiment 1.

[FIG. 4]

FIG. 4 is a diagram illustrating a configuration example of a sharedtable in Embodiment 1.

[FIG. 5]

FIG. 5 is a diagram illustrating a configuration example of a deviceconfiguration table in Embodiment 1.

[FIG. 6]

FIG. 6 is a diagram illustrating a configuration example of a RAIDconfiguration table in Embodiment 1.

[FIG. 7]

FIG. 7 is a diagram illustrating a configuration example of a volumeconfiguration table in Embodiment 1.

[FIG. 8]

FIG. 8 is a diagram illustrating a configuration example of an I/Ocontrol program in Embodiment 1.

[FIG. 9]

FIG. 9 is a diagram illustrating a configuration example of a virtualdevice configuration table in Embodiment 1.

[FIG. 10]

FIG. 10 is a diagram schematically illustrating a logical configurationexample of a storage in Embodiment 1.

[FIG. 11]

FIG. 11 is a flowchart illustrating a processing example of a virtualdevice configuration section in Embodiment 1.

[FIG. 12]

FIG. 12 is a flowchart illustrating a processing example of an I/Osorting section in Embodiment 1.

[FIG. 13]

FIG. 13 is a diagram schematically illustrating a logical configurationexample of the storage control program in Embodiment 1.

[FIG. 14]

FIG. 14 is a sequence diagram of I/O processing in Embodiment 1.

[FIG. 15]

FIG. 15 is a flowchart illustrating a processing example of a modeswitching section in Embodiment 1.

[FIG. 16]

FIG. 16 is a flowchart illustrating a data migration processing examplein Embodiment 1.

[FIG. 17]

FIG. 17 is a diagram schematically illustrating the data migrationprocessing in Embodiment 1.

[FIG. 18]

FIG. 18 is a block diagram for explaining a configuration example of acomputer system in Embodiment 2.

DESCRIPTION OF EMBODIMENTS

Embodiments of the present invention will be described below by usingthe drawings.

In the following embodiments, since portions having the same structuralparts and given the same reference numerals perform the same operationsin principle, duplicated explanation is omitted.

Embodiment 1

A first embodiment of the present invention will be described below byreferring to FIGS. 1 to 18. The embodiments are only an example forrealizing the present invention and care should be taken that they donot limit a technical scope of the present invention.

FIG. 1 is a block diagram illustrating a configuration example of acomputer system in this embodiment. The computer system in thisembodiment is provided with one or more nodes 10. The node 10 isprovided with one or more memories 11, a CPU (Central Processing Unit)12, an I/O (Input/Output) device 13, an NIC (Network Interface Card) 14,and storage device groups 15 and 16 in the node 10. Here, the storagedevice groups 15 and 16 are groups of a plurality of storage devices.Moreover, the storage device groups 15 and 16 are different in type. Forexample, one of them is a Hard Disk Drive (HDD), while the other is aSolid State Drive (SSD) or the like. Moreover, the I/O device 13 is anyone of an HBA (Host Bus Adaptor), a CNA (Converged Network Adapter), anHCA (Host Channel Adaptor), a PCIe extender and the like. In thisembodiment, as a preferred embodiment of the invention, a form in whichtwo types of devices, that is, a high-speed device and a low-speeddevice are coupled to the node 10, but the number of types of the deviceis not limited to 2 but may be 1 type or three types or more.

The memory 11 of the node 10 is provided with a logical partitioningprogram 100, an I/O control program 110, a storage control program 120,a shared table 130, and one or more OS (Operation System)/applications150. The logical partitioning program 100 constructs one or more logicalpartitions on the node, and the OS can be operated independently in eachlogical partition. The I/O control program 110 controls an I/O requestfrom the OS/application 150. The storage control program 120 providesfunctions including a management function of the storage device groups15 and 16, a shared storage function of receiving and responding to astorage I/O from inside the node or from outside the node, a function ofdata protection, data copying and the like. The shared table 130 holdsinformation to be shared by the I/O control program 110 and the storagecontrol program 120. That is, the memory 11 comprises a shared portionincluding the shared table 130, a portion for compute partition, and aportion for storage partition.

Moreover, the computer system is provided with a network 20, amanagement computer 30, a memory 31 of the management computer 30, a CPU32, an NIC 33, and a management program 35. The management computer 30and the network 20 are not indispensable, and the management program 35may be provided in one of the nodes 10 so that the entire computersystem is managed, for example.

The management program 35 manages the entirety of this computer system.The management computer 30 can obtain necessary information from thenode 10 and can control the node 10 via the network 20.

Moreover, a storage apparatus 40 is coupled to the node 10. Here, thestorage apparatus 40 is a shared storage apparatus such as a SAN(Storage Area Network) storage apparatus 40 or the like. The storageapparatus 40 is not indispensable. In this embodiment, the storageapparatus 40 is used as equipment including various storage functions byusing the storage device as a storage medium.

FIG. 2 illustrates a logical configuration example of the node 10. Inthis embodiment, in the node 10, a compute partition 101 and a storagepartition 102 as logical partitions are constructed by the logicalpartitioning program 100. Here, the logical partitioning program 100 canlogically partition hardware resources such as the CPU 12, the memory11, the I/O device 13, the storage device groups 15 and 16 provided inthe node 10 and assign them to each logical partition. As an assignmentmethod, a specific hardware resource is given priority and is assignedto a specific logical partition so as to guarantee a performance of theresource or to limit a range affected by a failure. Moreover, thehardware resource can be also shared, and that is realized by assigninga specific physical hardware resource to a plurality of logicalpartitions in shared.

In this embodiment, in the compute partition 101, the I/O controlprogram 110 and the OS/application 150 are held on the memory 11 and areexecuted by the CPU 12. In the storage partition 102, the storagecontrol program 120 is held on the memory 11 and is executed by the CPU12. To the storage partition 102, the storage device group 16 isassigned. Moreover, a shared storage section 103 and the storage devicegroup 15 are assigned to and shared by both the compute partition 101and the storage partition 102. The shared storage section 103, here, isa part of the memory 11 on the node 10 and holds the shared table 130.In this embodiment, the I/O control program 110 is present in thecompute partition 101, but the I/O control program 110 may be a part ofthe logical partitioning program 100.

FIG. 3 illustrates a block diagram of the storage control program 120 ofthis embodiment.

A device management module 121 manages a device configuration and a RAID(Redundant Array Inexpensive Disk) configuration of the storage devicegroups 15 and 16 assigned to the storage partition 102. The managementof the device configuration, here, means management of whether or notthe storage device can be shared by the storage partition 102 and thecompute partition 101, the storage device is used in the RAIDconfiguration or used as a device capable of direct access (hereinafterreferred to as a Raw access), and this management information is held inthe device configuration table 131. Moreover, the device managementmodule 121 can instruct the logical partitioning program 100 to changeassignment of the storage device to the logical partition. Moreover, themanagement of the RAID configuration means that the RAID level and theconfiguration of the storage device are managed, and this managementinformation is held in a RAID configuration table 132. The devicemanagement module 121 is provided with a management GUI (Graphical UserInterface) and an API (Application Programming Interface).

The I/O processing module 122 executes cache control to an I/O requestfrom a host, an I/O access I/O request to a RAID configuration module123 and an External storage connecting module 124, and a response to ahost. Moreover, the I/O processing 122 is provided with functionsspecific to a storage apparatus such as copying, snapshot, backup,mirroring, tiering and the like. The host, here, is the computepartition 101 in the node 10 or another node or server outside the node10 provided with the storage control program.

The RAID configuration module 123 executes conversion processing of anI/O request to a logical block address and a physical block address andexecutes the I/O request to the storage device.

The External storage connecting module 124 comprises a logical volumecorresponding to the storage device and the storage apparatus 40 inorder to make a Raw access to the storage device and the storageapparatus 40 and executes the I/O request to the storage device and thestorage apparatus 40.

The device driver 125 includes a driver of the storage device, a driverfor coupling to the compute partition 101, and a driver of the I/Odevice 13.

FIG. 4 illustrates a block diagram of the shared table 130 of thisembodiment. A volume configuration table 126, a device configurationtable 131, a RAID configuration table 132, and a virtual deviceconfiguration table 133 will be described in detail in FIGS. 7, 5, 6 and9, respectively.

FIG. 5 illustrates the device configuration table 131 of thisembodiment. A column 501 holds an identifier 501 of the storage device.The storage device, here, is a unit obtained by logically partitioning aPCI-SSD board by SSD unit, PCI-SSD board unit and SR-IOV (Single RootI/O Virtualization) and the like. As the storage device identifier, anumber of a Bus, a Device, a Function of the PCI of the applicabledevice or the like is used. A specific identifier may be given and usedas a storage device identifier if it is capable of identification.

A column 502 holds whether the storage device can be shared by thestorage partition 102 and the compute partition 101 or not. Thisinformation is held or obtained by API on the basis of the specificationof the storage device. A column 503 identifies whether the storagedevice is used in the RAID configuration or in Raw access. If “RAID” isentered here, it is used in the RAID configuration, and if “Raw” isentered, it is used in the Raw access. This table 131 may be created bythe storage control program 120, the I/O control program 110 or themanagement program 35 or may be stored in advance.

FIG. 6 illustrates the RAID configuration table 132 in this embodiment.A column 601 holds an identifier of an array group. The column 601 holdsa RAID level (information such as RAID0, 1, 5, 6 and the like) of thearray group and a data drive number n and a parity drive number m as“nD+mP” as the RAID configuration. A column 603 indicates an identifierof the storage device belonging to the array group. This storage deviceidentifier corresponds to the column 501 of the device configurationtable 131. This table 132 may be created by the storage control program120, the I/O control program 110 or the management program 35 or may bestored in advance.

FIG. 7 illustrates the volume configuration table 126 in thisembodiment. A column 701 holds an identifier of a volume. A column 702holds a storage device corresponding to the volume. Here, in the case ofthe RAID-configured storage device, “AG1” or the like is described as anidentifier of an array group. In the case of the storage device with Rawaccess, “storage device 1” or the like is described as an identifier ofthe storage device. In the case of the storage apparatus 40 which is aRaw-access storage outside the node, “storage apparatus x” or the likeis described. Moreover, if a mirror volume having the same contents as aspecific volume is logically comprised, “VOL a mirror” or the like isdescribed for the mirror of the volume “VOL a”, for example.

A column 703 holds an identifier of a host at an assignment destination.The assignment, here, indicates that the volume is accessible from thehost. Here, the compute partition 101 in the node is described as, forexample, by combining identification information such as an identifierof a logical partition at an assignment destination as “APP LPAR1” andan identifier of a logical volume to the logical partition (LUN (LogicalUnit number) and the like, for example) as a, b, c . . . , “APP LPAR1-a”or the like. Moreover, in the case of a host outside the node, anidentifier of a WWN or SCSI Name is held. Furthermore, if there is noassignment destination, “none” is described. This table 126 may becreated by the storage control program 120, the I/O control program 110or the management program 35 or may be stored in advance.

FIG. 8 illustrates a block diagram of the I/O control program 110 ofthis embodiment.

A virtual device configuration module 111 comprises a virtual device asa block device accessed from the OS/Application 150. A detailed flowwill be described in FIG. 11.

A mode switching module 112 is provided with a function of switching apath of the I/O access from the OS/application 150 to the storage.

An I/O sorting module 113 is provided with a function of sorting the I/Oaccess to the storage by mode. The detailed flow will be described inFIG. 12.

A RAID configuration module 114 executes conversion processing of theI/O request to the logical block address and the physical block addressand executes the I/O request to the storage device.

A device driver 115 is a driver of the storage device, a driver to becoupled to the storage partition 102, and a driver of the storage I/O.

FIG. 9 illustrates the virtual device configuration table 133 in thisembodiment. A column 901 holds an identifier of a logical partition ofthe compute partition 101 in the node as an identifier. A column 902indicates an identifier of a target virtual device in the logicalpartition. This identifier is an identifier of the virtual deviceconfigured by the virtual device configuration module 111 of the I/Ocontrol program 110. If there are a plurality of them, they areenumerated with “,”. A column 903 holds whether the virtual deviceincludes a plurality of paths or not. In this embodiment, if they areincluded it is described as “Yes” and if they are not, it is describedas “None”. A column 904 indicates a mode of the virtual device.

Here, a “first path” indicates a case where a path of accessing astorage device via the storage control program 120 of the storagepartition 102 is used as an I/O access path to the device. A “secondpath” indicates a case where the storage device is directly accessedfrom the compute partition 101. If the first path is used, here, thedata protection function and the data control function and the likeprovided in the storage control program 120 can be used. On the otherhand, if the second path is used, the storage control program 120 isbypassed and the storage device is directly accessed, whereby theperformance of the storage device can be effectively exerted.

Moreover, the column 905 holds the identifier of the device connectedthrough the path in the column 904 as an I/O access destination. Forexample, since the column 904 for an I/O of a virtual device B is thesecond path, the transmission destination 905 has a device identified as2b.

A column 906 holds a RAID level and a configuration of the virtualdevice. If “Raw” is entered, it is not a RAID configured device. If adevice with RAID configured is a target, the RAID level and theconfiguration are described as “RAID5(4D+1P)” or the like. This is equalto the column 602 of the RAID configuration table 132.

FIG. 10 illustrates a logical configuration of a storage of thisembodiment. The storage device group 15 includes a RAID area 942 as aset of storage devices in each of which RAID is configured and a Rawarea 943 as a set of storage devices capable of a direct access. Thestorage device group 16 also includes a RAID area 941. The RAID areas941 and 942 and the Raw area 943 are made to correspond to volumes 931,932, and 933, respectively, by the storage control program 120 of thestorage partition 102. Moreover, the volumes 931, 932, and 933 are madeto correspond to devices 911, 912, and 913 recognized by the I/O controlprogram 110 of the compute partition 101, respectively. Moreover, theRAID area 942 and the Raw area 943 are made to correspond to devices 922and 923 of the compute partition 101. Here, the RAID area 942 and thedevice 922 may be a plurality of storage devices.

A virtual device 910 which the I/O control program configures and showsto the OS/application 150 corresponds to the devices 912 and 922, thevirtual device 920 corresponds to the devices 913 and 923, and thevirtual device 930 corresponds to the device 911. Here, even if thedevice 922 includes a plurality of devices, it is converted to thesingle virtual device 910 by the RAID configuration module 114 of theI/O control program 110. The virtual devices 910 and 920 are providedwith I/O access paths by a first path 1701 and a second path 1702, andin the first path, the I/O control program 110 executes the I/O accesscorresponding to the devices 912 and 913, respectively, while in thesecond path, the I/O access corresponding to the devices 922 and 923 isexecuted, respectively.

Though not shown, regarding the I/O access from the device 922 to theRaid area 942, the RAID control is executed through the RAIDconfiguration section operating on the compute partition 101.

FIG. 11 illustrates a processing flow of the virtual deviceconfiguration module 111 in the I/O control program 110 of thisembodiment. At Step 1001, the virtual device configuration module 111executes identification of a device. The identification here meansidentification of whether the device (911, 912, 913, 922, and 923 inFIG. 10) corresponding to the compute partition is the device (911, 912,and 913 in FIG. 10) corresponding to the volume configured by thestorage control program 120 of the storage partition 102 or the device(922 and 923 in FIG. 10) directly corresponding to the storage device.Here, the virtual device configuration module 111 refers to the volumeconfiguration table 126, for example, and identifies the devicecorresponding to the volume configured by the storage control program120 of the storage partition 102 on the basis of the identifier of thelogical volume in the column 703 (LUN or the like) and OS or deviceinformation recognized by the device driver 125. Subsequently, at Step1002, the virtual device configuration module 111 obtains a storagedevice identifier of each device. Here, first, the virtual deviceconfiguration module 111 refers to the column 702 of the volumeconfiguration table 126 and the columns 601 and 603 of the RAIDconfiguration table 132 and specifies the storage device identifier tobe accessed by the volume for the device (911, 912, and 913 in FIG. 10)corresponding to the volume configured by the storage control program120. For example, the target of a volume “VOL c” in FIG. 7 is a “storagedevice 1” and the target “AG1” of a volume “VOL b” corresponds to anarray group “AG1” in FIG. 6, and the device identifier is “storagedevice 3, 4”. Subsequently, the virtual device configuration module 111obtains a storage device identifier of the device for the device (922and 923 in FIG. 10) directly corresponding to the storage device. As amethod of obtaining, the identifier is obtained via a device driver, OS,and firmware such as BIOS and EFI, for example.

At Step 1003, the virtual device configuration module 111 determineswhether there is a set of devices corresponding to the same storagedevice in the multiple paths. Here, the virtual device configurationmodule 111 obtains a set of devices whose storage device identifiersobtained at Step 1002 match between the device (911, 912, and 913 inFIG. 10) corresponding to the volume configured by the storage controlprogram 120 and the device (922 and 923 in FIG. 10) directlycorresponding to the storage device. In the example in FIG. 10, the setsof the devices 912 and 922 and the devices 913 and 923 are applicable.If there is a set of the devices, the routine proceeds to Step 1004 andif not, the virtual device configuration module 111 moves to Step 1005.At Step 1004, the virtual device configuration module 111 configures avirtual device. Here, the virtual device configuration module 111configures a virtual device corresponding to the set of the devicesobtained at Step 1003. In the example in FIG. 10, the virtual device 910is configured to the set of the devices 912 and 922 and the virtualdevice 920 is configured to the set of devices 913 and 923. At Step1005, the virtual device configuration module 111 configures the virtualdevice corresponding to the applicable device. In FIG. 10, the virtualdevice 930 corresponding to the device 911 is configured. However, theconfiguration of the virtual device at this step is not indispensableand the OS/application 150 may directly use the device 911.

At Step 1006, the virtual device configuration module 111 updates thevirtual device configuration table 133. Here, the identifier of theconfigured virtual device is entered in the column 902, and if thevirtual device is configured at Step 1004, “Yes” is entered in thecolumn 903, while if the virtual device is configured at Step 1005,“None” is entered in the column 903. Moreover, for the columns 904 and905, it is assumed that a path according to default setting arbitrarilyconfigured by a user or the like is selected. In the column 906, theRAID level/configuration is registered. If the RAID is configured forthe target device of the virtual device created at Step 1004 and Step1005, the RAID level and configuration are registered therein, while ifnot, “Raw” is registered. The case where the RAID has been configured isthat the target (column 702) of the volume configuration table 126 tothe applicable device at Step 1001 is the array group (“AG1” or thelike). At Step 1007, if there is an unconfigured device for which thecorresponding virtual device is not configured for the device detectedat Step 1001, the virtual device configuration module 111 moves to Step1002.

FIG. 12 illustrates a processing flow of the I/O sorting module 113 inthis embodiment. At Step 1101, the I/O sorting module 113 receives anI/O request to the virtual device from the OS/application 150. At Step1102, the I/O sorting module 113 determines an access mode to theapplicable virtual device. Here, the I/O sorting module 113 refers tothe virtual device configuration table 133 and if the mode of theapplicable virtual device (column 904 in FIG. 9) is the “first path”,the routine goes to Step 1103, while if it is the “second path”, theroutine goes to Step 1104. The determination may be made from theidentifier of a transmission destination by referring to the column 905.At Step 1103, the I/O sorting module 113 sorts the I/O access to thedevice of the first path corresponding to the applicable virtual device.Here, the device of the first path is a device (devices 912 and 913 inFIG. 10) corresponding to the volume configured by the storage controlprogram 120 of the storage partition 102. At Step 1104, the I/O sortingmodule 113 obtains whether or not the device corresponding to thevirtual device at the access destination configures the RAID. Thisindicates a case where the column 906 to the applicable virtual deviceof the applicable host in the virtual device configuration table 133 isnot “Raw”.

Regarding the access mode to the virtual device, such a case is expectedthat a user selects an access path of data in accordance with a use caseusing the data of the system in introduction of the system. The “firstpath” is selected if the user wants to use functions provided in thestorage control program 120. The functions here mainly include snapshot,backup, disaster recovery, thin provisioning, data migration,virtualization of storage tiers and the like. On the other hand, the“second path” is selected if the user wants to effectively bring out thedata access functions without using the above-described functions.

At Step 1105, the I/O sorting module 113 moves to Step 1106 if the RAIDis configured or to Step 1107 if not on the basis of the informationobtained at Step 1104. At Step 1106, the I/O sorting module 113 executesRAID area access processing by the RAID configuration module 123 for thedevice of the second path corresponding to the applicable virtualdevice. Here, the device of the second path is a device directlycorresponding to the storage device. In the RAID area access processing,the processing such as conversion of the I/O access request to thephysical address and the logical address of the storage device,appropriate partitioning/integration of the access processing to thetarget device, parity calculation and writing in the device duringwriting access and the like on the basis of the RAID level/configurationindicated by the column 906 of the applicable virtual device of theapplicable host in the virtual device configuration table 133. As aresult, reading/writing with respect to the device in which the RAID isconfigured is realized. At Step 1107, the I/O sorting module 113 sortsthe I/O access request to the device of the second path corresponding tothe applicable virtual device.

FIG. 13 illustrates a logical block configuration of the storage controlprogram 120 in this embodiment. An access is made to the storage device(941 and 942 in the figure) in which the RAID is configured via thedevice driver 125 corresponding to each of the storage device groups 15and 16 via the RAID configuration module 123, and in the case of theRaw-accessed storage device (943 in the figure) or the external storageapparatus (storage apparatus 40 in the figure), an access is made viathe External storage connecting module 124.

The Raw-accessed VOL C (933) is the Raw area 943 on the storage deviceand has no RAID configuration. Thus, if an access is made to the Rawarea 943 through the RAID configuration module 123, data cannot berecognized correctly. Thus, if an access is to be made to the Raw area943, as in this figure, the access is made via the External storageconnecting module 124 so that the Raw area 943 can be used while usingthe storage partition 102.

FIG. 14 illustrates a sequence of an I/O access in this embodiment. Ifthe mode of the target virtual device of the I/O request from theOS/application 150 is the “first path” and the RAID configuration is“RAID” (1301 in the figure), an access is made to the storage device viathe storage control program 120. On the other hand, if the mode of thetarget virtual device of the I/O request is the “second path” and theRAID configuration is “RAID” (1302 in the figure), an access is made tothe storage device not via the storage control program 120 but via theRAID configuration module 114 of the I/O control program 110. Moreover,if the mode of the target virtual device of the I/O request is the“second path” and the RAID configuration is “Raw” (1303 in the figure),an access is made to the storage device not via the storage controlprogram 120 or the RAID configuration module 114. As a result, the I/Oaccess performance becomes high speed in order from 1301, 1302, and1303, while 1301 is provided with functions of the storage controlprogram 120 and 1301 and 1302 are provided with the functionality of theRAID.

FIG. 15 illustrates a processing flow of the mode switching module 112of this embodiment. At Step 1401, the mode switching module 112 receivesa mode switching request. Regarding the mode switching request, the modeswitching module 112 is provided with an interface (GUI, API and thelike) to a user or an application, for example, and receives the requestfrom the interface. The received contents are a virtual device as atarget of the mode switching and a type of the mode at the switchingdestination. At Step 1402, the mode switching module 112 moves to Step1403 if the received request is switching to an access mode to thesecond path or moves to Step 1406 if it is switching to the first path.If the virtual device configuration table 133 is referred to and themode of the virtual device is already the same as the mode at theswitching destination, processing of the mode switching module 112 isfinished.

At Step 1403, the mode switching module 112 waits for I/O completion ofthe device driver 115 in the compute partition 101. Subsequently, atStep 1404, the mode switching module 112 waits for execution completionof the I/O request to the volume corresponding to the applicable virtualdevice in the storage control program 120. Here, a completion notice ismade by the storage control program 120 and the mode switching module112 via an information exchange interface or the like. At Step 1405, themode switching module 112 changes the mode of the applicable virtualdevice of the virtual device configuration table 133 to the second path.On the other hand, at Step 1406, the mode switching module 112 waits forI/O completion of the device driver 115 in the compute partition 101.Subsequently, at Step 1407, the mode switching module 112 changes themode of the applicable virtual device of the virtual deviceconfiguration table 133 to the first path.

The switching of the access mode may be dynamically changed by adiscrimination program to be provided in the I/O control program 110. Inthis case, the I/O control program 110 collects performance informationfrom access frequency from the OS/application 150 to the virtual device,OS/application 150, the file system, the driver or the storage controlprogram 120 and detects portions which become I/O queues or I/Oprocessing necks. As a result, switching is made from the first path tothe second path for data with I/O access frequency higher than apredetermined threshold value or data in which waiting for I/Oprocessing occurs more frequently than the others in the OS/application150, the file system, and the driver. On the other hand, switching ismade from the second path to the first path for the data with I/O accessfrequency lower than the predetermined threshold value or data in whichwaiting for I/O processing occurs less frequently than the others. As aresult, the access path can be optimized in accordance with data andhigher performance improvement can be realized.

Moreover, the I/O control program 110 provides a user with GUIspecifying a threshold value for performing the above-described pathswitching through the management computer 30. Specific examples of thethreshold value include a threshold value as an index for determiningthe above-described I/O queue or I/O processing neck and a thresholdvalue of I/O access frequency.

The method of using the RAID area 941 and the Raw area 943 separatelyhas been described for the storage device groups 15 and 16.Subsequently, a method of moving the data stored in the RAID area 941and the Raw area 943 to another area by means of data migration and notonly presence of use of the storage control program 120 but of furtherusing the RAID area 941 and the Raw area 943 separately in accordancewith use applications of the data will be described by using FIGS. 16and 17.

For example, such a case is expected that data of processing with highimportance placed on data protection such as online transactionprocessing and significant processing such as a core system is stored inthe RAID area 941 and the data is moved from the RAID area 941 to theRaw area 943 if a part of the data is used so as to execute dataanalysis processing or the like. As a result, a more flexible systemaccording to the use application of the data can be provided to a user.

Here, if the data is migrated from the RAID area 941 to the Raw area 943in the migration, there is a problem that processing of the systemcannot be stopped for the data migration. In a method described in FIGS.16 and 17, in the I/O control program 110, the data temporarily held ina device for migration is selected as an access path so that the data ismigrated without a stop and the above-described problem can be alsosolved.

FIG. 16 is a processing flow in which data migration processing isexecuted in the management program 35 in this embodiment. At Step 1601,the management program 35 (1) instructs the storage control program 120to create a second volume as a mirror volume of a first volume, and atStep 1602, the management program 35 (2) instructs the I/O controlprogram 110 to create a virtual device. Here, the second volume isassociated as a first path of the virtual device and the Raw area 943 ofthe storage device as a second path. At Step 1603, the managementprogram 35 (3) instructs the storage control program 120 to create athird volume coupled to the Raw area 943 as an external storage. At Step1604, the management program 35 (4) instructs the storage controlprogram 120 to synchronize the second volume with the third volume. AtStep 1605, the management program 35 (5) instructs the I/O controlprogram 110 to change mapping to the third volume as the first path ofthe applicable virtual device after synchronization at Step 1604 iscompleted. As a result, the contents stored in the existing first volumecan be migrated to a state capable of being accessed from the secondpath while capable of being accessed in the compute partition 101.

FIG. 17 is a block diagram of the data migration processing illustratedin FIG. 16. Here, the first volume may be a volume corresponding to theexternal storage apparatus 40. Reference numeral 1701 in the figurecorresponds to Step 1601 in FIG. 16, 1702 to Step 1602, 1703 to Step1604, 1704 to Step 1604, and 1705 to Step 1605.

Moreover, the data migration from the Raw area 943 to the RAID area 941can be also realized by the similar method.

Though not shown, the above-described system and apparatus are providedwith configurations required for executing processing as an informationprocessing device such as input/output devices represented by a displayand a keyboard, for example, and processing at each section is executedby the respective hardware in connection. Moreover, each processing canbe realized by hardware by a processing section for executing that byforming an integrated circuit or the like. The same also applies to anembodiment below.

Embodiment 2

Embodiment 2 is a system in which a node is separated to each of alogical partition which is a compute partition and a logical partitionwhich is a storage partition without using logical partitioning and isrealized by separate computers, and similarly to Embodiment 1, acomputer system capable of flexible use according to user needs for thecase where high-speed access is desired to a storage device and a casewhere data protection is desired will be described.

FIG. 18 is a block diagram illustrating a configuration example of asecond embodiment of the present invention. What is different fromEmbodiment 1 is that the storage device group 15 is shared by aplurality of the nodes 10 and 1800 through a shared bus 1840 between thenodes and that the node 10 holds the storage control program 120, theOS/application 150 and the I/O control program 110 for the node 1800,and a table 1850 equivalent to the shared table 130 in Embodiment 1 ineach table. The table 1850 synchronizes contents through the network 20between the nodes and the shared bus 1840. Here, the node 1800corresponds to the compute partition 101 in Embodiment 1.

As a result, by separating the resources between the OS/application 150and the storage control program 120, interference of the resources canbe eliminated.

The above-described Embodiment was explained such that the I/O controlprogram 110 has the I/O sorting means but it may be so configured that aprogram for realizing the I/O sorting means and related information maybe introduced into a computer. Moreover, the program for realizing theI/O sorting means may be stored in a storage device in the computer oran external storage apparatus in advance or may be introduced into theexternal storage apparatus when necessary through a detachable storagemedium or a communication medium (network of wired, wireless, opticaland the like or by means of a carrier wave or a digital signal on thenetwork).

REFERENCE SIGNS LIST

-   10 node-   11 memory-   12 CPU-   13 I/O device-   14 NIC-   15, 16 storage device group

1. A computer system comprising: a CPU and storage devices providingRAID (Redundant Array of Inexpensive Disks) areas, in which data isstored with RAID configuration and Raw areas, which are accesseddirectly and in which data is stored without RAID configurations,wherein the CPU is configured to: provide at least a first logicalpartition and a second logical partition by partitioning physicalresources including the CPU and the storage devices, wherein CPUresources allocated to the first logical partition are configured to:provide one or more virtual devices to an application, receive a firstI/O (input/output) request from the application and access the Raw areabased on the first I/O request, receive a second I/O request form theapplication and transmit a request to the second logical partition basedon the second I/O request, wherein the CPU resources allocated to thesecond logical partition control access to the RAID area with RAIDcontrol function.